Controllable constant flow regulating lift valve

ABSTRACT

The present invention relates to a controllable constant flow regulating lift valve of a direct-acting automat ic control type that operates on an operating force derived from the condition of a working fluid, such as valve-inlet pressure prevailing in the inlet passage, valve-outlet pressure prevailing in the outlet passage, variation of liquid level on the side of the outlet and so on. The flow regulating valve comprises a flow regulating valve structure and a slide valve structure for automatic flow restriction control. In the controllable constant flow regulating lift valve, axial thrust acting on the spindle of a lift valve type flow regulating valve structure is balanced such that the constant flow regulating lift valve can be operated for constant flow regulation by a very small power. When the flow regulating valve structure and/or the slide valve structure are clogged with soil, sand and dirt, the internal pressure changes to open the clogged valve for automatic cleaning operation so that the soil, sand and dirt are washed away. This constant flow regulating lift valve is suitably applicable to a variety of industrial fields.

TECHNICAL FIELD

The present invention relates to a direct-acting controllable constantflow regulating lift valve, namely, a controllable constant flowregulating lift valve without pilot valve, to be installed in a liquidtransportation line, provided with an automatic flow restrictionregulating passage, capable of operating on the basis of a working forcederived from dynamic parameters of the working fluid, such as thevalve-inlet pressure, the valve-outlet pressure and the variation of theoutlet liquid level, said lift valve having valve members so associatedthat the axial thrust acting on the spindle is balanced to reduce valveoperating power to the least extent, said lift valve being capable ofbeing easily fabricated regardless of its dimensions. The presentinvention also relates to a valve having a self-cleaning function toavoid the deposition of soil, sand and dirt that may obstruct theoperation of the valve.

In this specification, "water" is the general term for liquids.

BACKGROUND ART

Conventional valves, such as butterfly valves and gate valves, are notencountered by troubles when used as simple shut-off valves. However,when used for regulating flow rate under severe conditions, such asconditions for transporting high-pressure water, the conventional valvesof this type are liable to generate drift currents and turbulencebecause the conventional valves, in general, have an irregular valveopening, and such drift currents and turbulence are liable to generatelarge noise and intense vibrations, to induce impulses, to cause rapidcorrosion and breakage of the main component parts of the valves. On theother hand, lift valves are less liable to generate drift currents andturbulence because lift valves have a regular valve opening. However,the lift valves once closed are difficult to open due to unbalancedaction of pressure on the valve element and the lift valves are unableto function properly if due attention is not paid. Therefore, it hasbeen a usual practice to use a double-seated lift valve in which theaxial thrust acting on the valve element is balanced or to use asingle-seated valve having a spindle integrally provided with abalancing piston which reduces the axial thrust that acts on the valveelement.

Nevertheless, the conventional lift valves still have many problems. Asmentioned above, an axial thrust reducing means for a high-pressure liftvalve or a large lift valve is complex and increases the manufacturingcosts of the lift valve significantly, and it is very difficult tocontrol flow rate in a pipe in which pressure varies violently. In liftvalves, as well as in valves of other types, troubles due to thedeposition of soil, sand and dirt are liable to occur when the liftvalves are adjusted to low flow rate and these troubles are difficultproblems to solve.

Accordingly, it is an object of the present invention to provide aneasy-to-use controllable variable flow regulating lift valve solvingthose problems of the conventional lift valves, capable of exertingstable flow regulating performance, requiring very small power for valveoperation, and provided with a flow regulating valve means and anautomatic flow restriction means capable of an automatic cleaningfunction to avoid clogging.

DISCLOSURE OF THE INVENTION

The present invention pertains to a valve in the technical field ofdirect-acting controllable constant flow regulating valves. The presentinvention is applied to a lift valve having a regular passage leastliable to generate violent turbulent currents or drift currents duringflow regulating operation, and comprising, as principal components, avariable flow regulating valve element, a slide valve element forautomatic flow restriction, and a valve body having an inlet passage, aflow damping chamber (middle chamber) and an output passage arranged inthat order along the direction of flow.

The flow regulating valve element and the slide valve element come intocontact with each other immediately before the flow passage is shut offto balance the axial thrusts. Consequently, the flow regulating valveelement can be operated for flow rate adjustment by a very small power.Accordingly, when the controllable constant flow regulating lift valveof the present invention is used for liquid level control or the like, asmall liquid level regulating float device may be employed, and the flowrate can be regulated in a linear relation with the variation of theliquid level.

In the controllable constant flow regulating lift valve of the presentinvention, the flow regulating valve is disposed so as to form abackward slide clearance so that the flow regulating valve element,similarly to a slide valve, can be lifted up from the valve seat whenclogging occurs for self-cleaning by the pressure of the fluid to avoidtroubles attributable to clogging. Therefore, the controllable constantflow regulating lift valve of the present invention is effectivelyapplicable to facilities that handle filthy liquids.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a controllable constant flow regulatinglift valve of a first embodiment according to the present invention;

FIG. 2 is a sectional view of a controllable constant flow regulatinglift valve of a second embodiment according to the present invention;and

FIG. 3 is a sectional view of the valve used for liquid level control.

BEST MODES FOR CARRYING OUT THE INVENTION

The present invention will be described in detail with reference to theaccompanying drawings. Referring to FIG. 1, a valve body 1 has an inletpassage a and an outlet passage e, and is provided with a bonnet 2. Thevalve body 1 has a flow regulating valve opening b formed between a flowregulating valve seat 3 and a flow regulating valve element 7 disposedopposite to the flow regulating valve seat 3. In the valve body 1 isformed a slide valve opening d between a slide valve seat 4 and a slidevalve element 10 disposed opposite to the slide valve seat 4. A flowdamping chamber c is formed between the valve openings b and d.

Thus, the interior of the valve body 1 is divided into the inletpassage, the flow damping chamber and the outlet passage in that orderalong the direction of flow of the fluid by the flow regulating valveelement and the slide valve element, and the flow is restricted at theflow regulating valve opening b and the slide valve opening d.

A sealed chamber f defined by the end wall 11 of the slide valve elementand the bonnet 2 is sealed with a sealing member 14, and communicateswith the inlet passage a by means of a connecting pipe 17. A balancingspring 13 is disposed so as to form an automatic restriction regulatingpassage in the slide valve opening d. The flow regulating valve element7 is axially slidably fitted on a spindle 6 in a water-tight fashion sothat a backward slide clearance g is formed, and is pressed against ashoulder 6q of the spindle 6 with a flow regulating valve spring 9.

Fundamentally, the flow regulating valve element 7 and the end wall 11of the slide valve element are substantially equal to each other inpressure receiving area, but the pressure receiving area of the end wall11 of the slide valve element is slightly greater than that of the flowregulating valve element 7. A boss 8 of the flow regulating valveelement comes in contact with a boss 12 of the slide valve element whenthe flow regulating valve element 7 is substantially seated on the flowregulating valve seat 3 and the flow rate is virtually zero. Upon thecontact of the boss 8 of the flow regulating valve element with the boss12 of the slide valve element, valve-inlet pressures acting respectivelyon the corresponding pressure receiving surfaces of the flow regulatingvalve element and the slide valve element substantially balance witheach other. Therefore, the controllable constant flow regulating liftvalve requires a very small valve operating power for the entire valveopening and closing stroke owing to the balanced action of thevalve-inlet pressures acting on the respective pressure receivingsurfaces of the flow regulating valve element and the slide valveelement combined with a very small force acting on the spindle duringthe flow regulating operation.

Referring to FIG. 1, when the flow regulating valve element 7 is at itsfully open position, the fluid flows from the inlet passage a throughthe flow regulating valve opening b, the flow damping chamber c and theslide valve opening d in that order into the outlet passage e. In thisstate, the force of the balancing spring 13 acting to open the slidevalve opening d is balanced with the difference between the pressuresacting on the front and the back side of the end wall 11 of the slidevalve element, i.e., between the pressure in the chamber f equal to thepressure in the inlet passage a, and the pressure in the flow dampingchamber c. Naturally, this pressure difference is created due to theresistance of the passage of the flow regulating valve opening b.

When the flow regulating valve element 7 is moved toward the valve seat3 for flow regulation, the resistance of the valve opening b increases,the pressure in the flow damping chamber c decreases accordingly, andthe balance established by the balancing spring 13 is lost, so that theslide valve element 10 moves automatically toward the slide valve seat 4to a position where the passage is adjusted to an opening correspondingto a desired flow rate and the slide valve element 10 is held stable atthe position. In this state, the unbalanced pressure acting toward thedownstream side, i.e., acting upward as viewed in FIG. 1, on the flowregulating valve element 7 corresponds to the slight resistance of thepassage in the flow regulating valve opening b, whose effect on theoperation of the spindle 6 is negligible.

When the flow regulating valve opening is almost closed or fully closedwith the flow regulating valve element 7, the pressure in the flowdamping chamber c decreases nearly to the valve-outlet pressure, and theboss 8 of the flow regulating valve element is in contact with the boss12 of the slide valve element, whereby as mentioned above, the axialthrusts are balanced. Thus, the controllable constant flow regulatinglift valve requires only a slight power for operating the spindlethroughout the stroke.

The flow regulating valve opening b of the constant flow regulating liftvalve of the present invention becomes narrow when adjusted for a smallflow rate. Then, the pressure in the flow damping chamber c dropsinstantaneously when the flow regulating valve opening b is clogged withsoil, sand and dirt and, consequently, the slide valve element 10 movesdownward to depress the flow regulating valve element 7 by a distance ina range corresponding to the backward slide clearance g to enlarge theflow regulating valve opening b in order that the soil, sand and dirtclogging the flow regulating valve opening b are washed away therefrom.When the slide valve opening d is clogged, the pressure in the flowdamping chamber c rises instantaneously to lift up the slide valveelement 10 and, consequently, the soil, sand and dirt clogging the slidevalve opening d are washed away therefrom.

There are various possible methods of operating the flow regulatingvalve element 7 for closing and opening the same. The constant flowregulating lift valve shown in FIG. 1 is of an inside screw type, inwhich the spindle has a threaded portion 6s screwed in a bearing 20.When the spindle 6 is rotated by turning a handle 18, the flowregulating valve element 7 is raised or lowered. Indicated at 5w is asupport plate for preventing the sealing member 14 from being caused toadhere to a partition wall 5 by high pressure or for any reason.

The spindle 6 may be supported on the valve body on the side oppositethe side on which the bonnet 2 is disposed, without fitting the slidevalve element 10 on the spindle 6. This modification does not affect theoperation of the controllable constant flow regulating lift valve of thepresent invention.

FIG. 2 shows a controllable constant flow regulating lift valveaccording to a second embodiment of the present invention. The constantflow regulating valve of the second embodiment is substantially the samein construction as the constant flow regulating lift valve of the firstembodiment, except that a flow regulating valve element 7 is disposedbehind a valve seat 3 with respect to the direction of flow of theliquid. A flow damping chamber c is formed between a flow regulatingvalve opening b and a slide valve opening d. The function and effect ofthe constant flow regulating lift valve of the second embodiment aresubstantially the same as those of the constant flow regulating liftvalve of the first embodiment.

In the second embodiment, a flow regulating valve element 7 is mountedon a spindle 6 supported by a valve element supporting member 15 and ispressed against a nut 16 on the spindle by a balancing spring 13 so thata backward slide clearance g is formed.

Fundamentally, the flow regulating valve element 7 and an end wall 11 ofa slide valve element are substantially equal to each other in pressurereceiving area. Actually, the pressure receiving area of the flowregulating valve element 7 is slightly greater than that of the end wall11. Therefore, the boss 8 of the flow regulating valve element and theboss 12 of the slide valve element come into contact with each other tobalance axial thrusts when the flow regulating valve element 7 is movednearly to its closing position. When the flow regulating valve opening bis clogged, the pressure in the flow damping chamber c dropsinstantaneously, so that the flow regulating valve element 7 is liftedup and matters clogging the flow regulating valve opening b can bewashed away.

The controllable constant flow regulating lift valve shown in FIG. 2 isof an outside screw type, in which the spindle 6 is provided with a keyway 6k for restraining the spindle 6 from rotation, and a handle 18 isscrewed on the threaded portion 6s. The handle 18 is turned to raise andlower the flow regulating valve element 7 for opening and closingoperation.

FIG. 3 shows the controllable constant flow regulating lift valve asused for a liquid level control. The spindle 6 of the constant flowregulating lift valve is moved by a float 21. Although the operation ofthe controllable constant flow regulating lift valve in this use issubstantially the same as that of the controllable constant flowregulating lift valve described with reference to FIG. 1, the liquid isdischarged very moderately even if the valve-inlet pressure prevailingin the inlet passage is high because the flow rate varies linearly withthe liquid level, so that the liquid is not supplied excessively.

Although the float 21 is connected directly to the spindle 6 in thisembodiment, naturally, the float 21 may be connected to the spindle 6 byany one of various conventional methods employing connecting members orlevers.

Although the present invention has been described in connection with thepreferred embodiments shown in FIGS. 1 to 3, the controllable constantflow regulating lift valve may be disposed with the spindle extended ina lateral position, the sealing member may be an O ring, an oil seal, adiaphragm or a bellophragm, and changes and variations may be madetherein without departing from the scope thereof.

INDUSTRIAL APPLICABILITY

The present invention makes good use of the advantages of theconventional lift valves that hardly generate violent turbulence andviolent drift currents, incorporates improvements into the direct-actingvalve so that the axial thrusts are balanced to reduce the powernecessary for operating the direct-acting valve to the least possibleextent. The present invention solves the problems in the conventionallift valves to provide a lift valve that can be formed with largedimensions and can be formed in a construction applicable to handlinghigh-pressure liquid. The controllable constant flow regulating liftvalve of the present invention has an excellent constant flow regulatingcharacteristic, can be driven for operation by the power of a largevariety of power sources including the buoyancy of a float and a solarpower generating system that generates only weak power. Since thecontrollable constant flow regulating lift valve of the presentinvention is capable of preventing troubles attributable to the cloggingof the valve opening, the constant flow regulating lift valve of thepresent invention is applicable to uses in various industrial fieldsincluding the field of agricultural irrigation and the field of civilengineering drainage.

We claim:
 1. A controllable constant flow regulating lift valve havingflow regulating valve means formed on an upstream side (inlet side) ofthe valve, sliding valve means provided for automatic flow restrictionregulating operation and formed on a downstream side (outlet side) ofthe valve, and a flow damping chamber (c) defined between the flowregulating valve means and the slide valve means; said controllableconstant flow regulating lift valve comprising:a partition wall (5) of avalve body (1); a slide valve element (10) slidably fitted in thepartition wall (5) with a sealing member (14) attached to the slidevalve element (10) for sealing; a valve seat member (4) disposedopposite to the slide valve element (10) so as to form a slide valveopening (d) between the valve seat member (4) and the slide valveelement (10); a valve spindle (6); a flow regulating valve element (7);a balancing spring (13) extended between an end wall (11) of the slidevalve element (10) and the flow regulating valve element (7) in parallelto the spindle (6) and exerting a predetermined force for expanding thevalve opening (d); a sealed chamber (f) formed between the end wall (11)and a valve bonnet (2) and connected to the inlet side (a) via aconnecting passage (17), the pressure receiving area of the flowregulating valve element (7) and that of the end wall (11) beingsubstantially equal to each other, a boss (8) of the flow regulatingvalve element (7) and a boss (12) of the slide valve element (10) beingformed so as to come into contact with each other when the flowregulating valve element (7) is almost seated on a valve seat (3) formedon the valve seat member (4), and the flow regulating valve element (7)being supported so as to be able to be moved away from the valve seat(3) by variation of the pressure in the flow damping chamber (c).
 2. Acontrollable constant flow regulating lift valve according to claim 1,wherein a float is connected to the spindle to drive the spindle.